kgg

@mbnaegle I can say I really enjoyed reading the history around these old machines. kgg

@PastorBob The ones similar to the Richards can be had off Temu for about $4 USD. The Richards which according to this article ( https://www.apparelnbags.com/blog/where-are-richardson-hats-made/ ) are made in China, Bangladesh, and Vietnam anyway. kgg

That is why a lot of us have more then one machine as some machines are a lot better then others at certain things. There is no one size that fits all situations and sometimes you need two machines to do one item. The closest all rounder for most are the Juki LS-1341 (or clone) with a table top attachment. Is it possible for your items to skive the edges down to reduce the thickness of the leather????? Let us known what you decide on. kgg

First off using Weaver Leather Thickness Chart ( https://www.weaverleathersupply.com/pages/leather-thickness?srsltid=AfmBOoqzN2JPG7btuXxjAntVnhbq3NjzasVYzvuTwaMaLRu6Y0adRV4J ) 16 oz of leather is going to be 1/4" (6.36mm) and add another 2 oz you are going to be at .281" ( 7.14mm). The max the spec say is 3/8" ( 9.53mm) which is going to give you less then 3/32" (2.39mm) wiggle room. That for me would knock that particular machine out as I would think you would always be pushing it to or near it's max. which I figure would reduce life expectancy. I would suggest looking at other alternatives maybe a Class 1341 cylinder arm machine similar to the Juki LS-1341 (or clone) but I don't do footwear. The Cobra Class 4 is NOT a post bed machine it is a cylinder arm Class 441 clone of the Juki TSC-441. These machines are meant to sew such items as holsters. They use a needle that is visually almost the same size as a 2 1/2" finishing nail. They weight in at about 125lbs for just the head alone verses a LS-1341 at 82 lbs. I would suggest: 1. read 2. either visit / telephone / sending a sample of what you want to sew to maybe someone like Toledo Industrial Sewing Machines ( www.tolindsewmach.com ). There is no one machine that will do everything. Buy a new machine that will do 90% of your items and get a second used machine to cover off the remaining 10 %. kgg

Yes typically they do. A example is I bought a new Juki DU-1181N during the China Cough for $900 CAD ( $650 USD ) now I see they are now about $2000 CAD ($1500 USD). kgg

After you read the article @AlZilla referenced. Consider my 90 % rule. If you are going to be doing 90 %of items that are: i) flat items like wallets and belts with a leather thickness of less then 3/8" get either a flatbed machine like a Juki DNU-1541S (or clone) or a cylinder arm machine with a flatbed table top attachment like a Juki LS-1341 (or clone) that way you can also sew bag type items. Buy New and look for a used machine that will cover off the other 10 %. ii) doing mostly holster type work get you really need a class 441 machine. Motorized like a Juki TSC-441 (or clone). Manual like a Tippmann Boss, Cowboy Outlaw or a Weaver Cub. These machines, motorized or manual, are meant for thick leather up to about 3/4", use heavy thread and use a needle that is the size of a 2 1/2" finishing nail. Buy New and look for a used machine that will cover off the other 10 %. What is your budget??????? Buy Once, Cry Once kgg

The problem that arises is when sewing multi layers like seams where seams cross etc. The more layers adds not only thickness but the layers can slip around when you are using a drop foot machine. No one machine will do everything. A flatbed machine is good for sewing flat items like belts / wallets etc. A cylinder bed machine is good for sewing items like bags etc. You can turn a cylinder bed machine into a flatbed machine by installing a flatbed table top attachment. The most common new industrial sewing machines for leather related sewing these days are compound feed (needle, presser foot, feed dog). I have a Juki DU 1181N walking foot machine for when I sew items that are less then 5mm (~3/16") thick and with thin thread (V69, V92) as my Juki DNU-1541S really hates thin stuff particularly if I use V69 thread and it has a tendency to want to suck fabric down into the needle plate. I would suggest taking a sample of your stuff to a brick / mortar store using the thread size you would like to use and give a few machines a go. As a note if the: i) Flatbed -- Juki DU 1181N would work for your stuff they cost about $1500 new. ii) Flatbed -- Juki DNU 1541S about $2500 and a clone like the Cowboy CB 1541S about $1600 iii) Cylinder Arm -- Juki LS-1341 about $5200 and a clone like the Cowboy CB 341 about $2400 A lot is going to come down to how thick your wallet is. Buy Once, Cry Once kgg

I would run not walk away at that price. Buy something from a manufacturer that is still in business. Nakajima 321L is a needle feed machine and for leather work you really need at least a walking foot machine. The Nakajima 321L is what the old Juki LS-341 was based on, according to the info I have seen, with some changes. The first Juki LS-341's if I'm not mistake began in the early 1970's. From that the Nakajima 321L is going to be will over 50 years old. With the Nakajima sewing company being part of the Juki company since the 60's or 70's finding the different parts could be difficult. What are you planning on sewing???? kgg

I agree. kgg

According to the manual it will take a #26 needle. The needles will leave a large hole about the size of a 2 1/2" finishing nail. If you don't have a manual here is a pdf version. kgg 20190619115045364.pdf

Incorrect. They typically have a lower startup rpm but depending on operator skill, startup rpm, manufacturer you may require a speed reducer regardless of servo motor type. If you are going to be sewing leather the needles you will need are 135 x 16 x needle size. Your machine will come with a 135 x 17 x needle size for fabric. Here is a good link to a chart showing needle size versus thread size vs thread strength ( https://www.tolindsewmach.com/thread-chart.html ). Don't cheap out, buy brand name needles and thread. Always buy two spools of thread, one for the top thread and one for the bobbin. That way you can fill a bobbin while you sew without having to un-thread the top thread to wind a bobbin. kgg

Keep in mind: i) Items like belts / wallets are best done on flatbed like a Juki DNU-1541S or clone. ii) Items like bags are best done on a cylinder arm machine like the a Juki LS-1341 or clone. iii) You can turn a cylinder arm machine into a flatbed machine by installing a flatbed attachment. If this is going to be your only machine I would suggest seriously looking at this option. That is one style of speed reducer typically referred to as a box style. You can also get the more common pedestal style. Both have their pro's and cons but do the job, speed reduction. Here is a photo I copied from Toledo Industrial Sewing Machines ( https://www.tolindsewmach.com/motors.html ) The motor shown in your photo is a brushed servo motor, good uncomplicated work horses. kgg

The safety clutch when it kicks in protects a lot of internal parts from getting damaged. Depending on how badly you screw up usually it is just a matter of resetting the safety and you are sewing again. If you jam the machine up and I think most of have at some point jammed a machine up the repair cost of the damaged parts will be be a lot greater then the $75 you "saved". As a side note my Juki DNU -1541"S" hates items less then 5mm thick and much prefers thicker items with V92 thread as a minimum top and bobbin thread size. Find another retailer one with experience doing leather work. What are the items you want to sew, how thick of leather and with what size of thread as a flatbed machine may not be your best option? kgg

Since you are in the US the Sailrite Workhorse is the same motor ( https://www.sailrite.com/Sailrite-Workhorse-Servo-Motor-110V ) at $299.95. The problem with any of the brushless servo motors is the high startup rpm's which is typically around 500 rpm and with both the Reliable and the Sailrite it is 400 rpm. This can create startup "jump". To help smooth out the startup "jump" of the brushless motors as well as slowing down the machine while giving more torque install a speed reducer pulley and replace the servo motor pulley with a 50 mm pulley. Typically the reduction is 3:1 (6" large pulley and a 2" small pulley). I would suggest you forget about the Juki DNU 1541 and purchase the Juki DNU 1541 "S". The Juki DNU 1541 has no safety clutch. kgg

To be 100 percent sure about the specs I would check with @CowboyBob he would know for sure and probably has a manual kicking around. kgg

Same as normal sewing machine oil like Lily White. kgg

The manual actually says 16.0 mm2/ sec. which is equal to 5W oil. kgg

Most people use regular sewing machine oil. Normally you would follow the manufacturers recommendation as outlined in the manual. Most people I think use a Lilly white sewing oil or a variant. Lilly white has a viscosity of 5W. As a note a higher viscosity will make the bearings carry the load better at lower speed, but maybe not great at prolonged higher speeds. I personally never use normal sewing machine oil in any of my machines old or new but that is my choice. I use a blend of synthetic motor and synthetic transmission oils. If the machine is old I will use a higher concentration of transmission oil to flush debris or dried oil out so the bearings can get fresh oil in there for lubrication. If there is minor wear in the bearings I use a higher concentration of motor oil. If I am doing regular oiling I use about 20 percent synthetic transmission oil in the blend. I find the synethic oil blend makes the machine run smoother and quieter. Just in case you don't have a manual for your machine I have included a pdf. Refer to page 4 "Oiling" for what the manufacturer recommends as far as oil and oiling interval. The problem of staining I find is caused by over oiling. kgg 1245 Owners Old Case.pdf

This machine from what I understand is: i) A drop feed needle feed machine. Not what I would attempt to use for holsters as you really need a compound sewing machine (feed dog, presser foot and needle) for leather work. ii) I would consider this more geared towards fabric then leather. iii) As far as sewing 1/2" I think this is very doubtful, at best maybe 3/8". iv) The thread limit I would suspect would be V92 maybe V138. How thick is the leather you are planning on sewing? What size of thread are you wanting to use? Are you sewing presently by hand or by machine??? The first I have ever heard of the shank size determining the sewing thickness. kgg

Sorry, early morning Nicotine level was low. Hadn't had my second cup of coffee and enough vaping. Use to be second cup of coffee and six smokes. kgg 341 engineer manual.pdf

Here is a copy of the Juki LS-431 engineering manual refer to section 9 page 12. kgg

If I'm not mistaken the fabric needles would be DDx1 which are 214x1 needles. I still would check with a Seiko dealer or your manual. kgg

I would say those made in Switzerland then either those made in Japan or Germany. The problem is getting screwdrivers that seat and fit properly as well as being durable so sometimes you need to go with metric sized screwdrivers to get a better fit to avoid screw head slop. kgg

The green arrow points to what looks like a oiling port for the internal parts similar to the Juki LU-562 & 563. The red arrow points to the stitch length adjuster as I don't see a stitch length adjusting dial or it is a safety clutch to protect the hook assembly when you jam up the machine. If you want to wind just a bobbin: Here is a link to pretty good video from the 9:00 minute mark ( i) remove thread from needle otherwise you will jam the machine up. ii) the winder needs to be set so it trips out when you get about 80 percent of the bobbin filled. iii) install empty bobbin on winder shaft. Most bobbins have holes on the sides of the bobbin so a) the end of the thread from the spool of thread you are using to fill the bobbin through the winders tension discs then to the inside of the bobbin outwards through a hole b) push the bobbin trip lever towards the rear of the machine to engage the winders drive wheel up against the machines drive belt c) hold the end of the thread in your hand d) hit the go pedal e) hold the end of the thread until you have at least two complete rows wound on the bobbin. iv) you really should have two spools of thread one for the top thread and one for the bobbin thread so you don't have to unthread the machine just to wind a bobbin. kgg

Industrial flatbed upholstery machines similar to the Juki dnu-1541 S and similar clones will typically sew 3/8" (9.5mm) while the cylinder arm machines similar to the Juki LS-341 or 1341 and clones will typically sew 7/16" (11mm). Once you go above that thickness and / or higher then V138 thread you need a a Class 441 machine, which the one armed bandits are, either manual or motorized. When I wanted a class 441 machine I choose to go with a motorized machine as for me I figured the bloom would quickly fade having to move that lever up and down for each stitch. The class 441 machines excel at thick / tough leather but can be dumbed down to thin stuff with smaller thread. I suggest you follow the 90 percent rule, doing mostly thinner flat items get a flatbed or a cylinder arm machine with a table top attachment. No one machine will do everything. Buy Once, Cry Once Here is a great article you should read to help figure out what machine would be needed for your stuff. kgg